Cable diagnostics tests
NOTE: The cable diagnostics test will bring down the link, which will take more time to complete the test.
The TDR cable diagnostic test allows an operator to test twisted pair cables for faults without physically disconnecting the cables from the switch. It helps in troubleshooting connectivity or monitoring performance on one or more switch ports.
The
diag cable-diagnostic command can be used to run cable diagnostic tests and display the test results.
The following table provides the cable status messages and their descriptions.
| Status | Meaning |
|---|---|
good |
The MDI pair is good. |
open |
The MDI pair is not terminated with a link partner or has an open circuit. |
short |
The MDI pair is shorted within itself (intra-short). |
inter_short |
The MDI pair is shorted with another pair (inter-short). |
high_impedance |
The MDI pair has high-impedance mismatch and is not guaranteed to link up. |
low_impedance |
The MDI pair has low-impedance mismatch and is not guaranteed to link up. |
failed |
The MDI pair has failed the cable diagnostic test. |
The following table provides the possible cable diagnostic failure reasons for port types.
| Port Type | Reasons |
|---|---|
| 1GbT | Interface is busy, or link partner is not configured for auto-negotiation, or link partner is busy establishing the link. |
| 2.5G-SmartRate | Interface is busy. |
| 5G-SmartRate | Interface is busy. |
The following table provides the cable length accuracy for port types.
| Port Type | Reasons |
|---|---|
| 1GbT | When diagnostic status is "good", cable length is reported within +/-10m. |
| 2.5G-SmartRate | When diagnostic status is "good", cable length is not reported (0m). |
| 5G-SmartRate | When diagnostic status is "good", cable length is not reported (0m). |
The following table provides the distance to fault accuracy for port types.
| Port Type | Reasons |
|---|---|
| 1GbT | When diagnostic status is not "good" or "failed", distance to fault is reported within +/-5m. |
| 2.5G-SmartRate | When diagnostic status is not "good" or "failed", distance to fault is reported within +/-5m. |
| 5G-SmartRate | When diagnostic status is not "good" or "failed", distance to fault is reported within +/-5m. |